3A Radiometer (GPROF)

Gridded rainfall estimates from GPM GMI, TRMM TMI, and constellation microwave radiometers

3GPROF, 'GPROF Profiling', produces global 0.25 degree x 0.25 degree gridded means using Level 2 Gprof data. Vertical hydrometeor profiles and surface rainfall means are computed. Various pixel counts are also reported. The PI is Joyce Chou. The product can be monthly or daily.

Processing Level
Current Algorithm Version
Dates Covered
June 2000 - Present
Minimum Latency
Daily (research)
Spatial Resolution
0.25 Degree
Date Last Updated
June 3rd, 2022
Document Description

The L3GPROF algorithm provides monthly and daily mean precipitation and related retrieved parameters from the Level 2 GPROF precipitation profiling algorithm for the GPM core and constellation satellites.

Each L3GPROF product contains global 0.25o x 0.25o gridded monthly/daily unconditional means and pixel counts. Monthly product filenames start with 3A-MO or 3A-CLIM-MO, and daily product filenames start with 3A-DAY or 3A-CLIM-DAY.

Date Last Updated
June 3rd, 2022
Document Description

This Level 3 GPROF Version 07 release involves the following changes from the previous
(Version 05) release:

1. Product format change:
Added dimension variables such as lat, lon, layer, lat_bnds, lon_bnds, layer_bnds. Removed
cloudIce variable but added graupel and latentHeating variables.
2. Total number of precipitation pixels (npixPrecipitation):
In Version 05, pixels with pixelStatus=0 and surfacePrecipitation > 0 are counted as
precipitation pixels. In Version 07, pixels with pixelStatus=0, surfacePrecipitation > 0 and

Date Last Updated
April 17th, 2018
Document Description

GPROF V05 is the rainfall algorithm used in TRMM V8. It matches in all ways the algorithm from the retrieval for GPM GMI and other satellites in the constellation. The Goddard Profiling Algorithm is a Bayesian approach that nominally uses the GPM Combined algorithm to create it's a-priori databases. Given the importance of these databases to the final product, they are worth reviewing before discussing particular changes to the algorithm. GPROF V03 was implemented at the launch of the GPM mission and thus had no databases from the GPM satellite itself.